Closure of tree cavities



April 7, 1931. E-PEETS 1,799,700

CLOSURE OF TREE CAVITIES Filed Sept.- 2'7, 192'? I NV EN TOR.

Patented Apr. 7, 1931 PATENT OFFICE ELBERT PEETS, OF CLEVELAND, OHIO CLOSURE F TREE CAVITIES Application filed September 27, 1927. Serial No. 222,377.

This invention concerns the art of tree surgery and its generalobject is the provision of an improved method of sealing tree cavities.

More specifically, my invention has for its object-the provision of a cavity closure adapted to withstand without injury all movements due to the bending of the tree or to changes of temperature, also to prevent the I ingress of water, insects, and fungi into the cavity while permitting, optionally, the ventilation of the cavity. A further object is to permit the healing of the Wound and the strengthening of the tree by the formation of a normal callus, the closure being arranged to permit the callus to roll into the cavity in the natural manner of callus growth.

, It will thus be seen that the object of the invention is to overcome the difficulties which have led to the abandonment, in recent years,

of the very .old practice of covering cavities with sheet metal. That method failed because tree movements or callus growth usually fractured the closure. More recently a slightly flexible closure has sometimes been used, but it followed the old assumption that it is possible and desirable to resist and support the healing callus, thus differing sharp-' ly in basic principle from the method of the I present invention, in which the natural inrolling of the callus is permitted, substantially without resistance or deformation. Other objects of my inventionwill become apparent from the following description re-- of a closure, showing a Wood shoulder; Fig. 5 is a similar view showing a metal stop taking the place of the shoulder, ig. 6 is a view showing the installation of a closure behind an old callus; and Fig. 7 is a cross section through the same.

The cavity is excavated and disinfected according to the usual methods, the details varying with the conditions. Around the mouth of the cavity a shoulder is cut in the wood 1, the shoulder having ashoulder floor 2 and a shoulder Wall 3. The shoulder Wall 3 is out through the bark 4;, the Cambium 5, and the outer part of the wood 1. The shoulder floor 2 is approximately concentric with the bark surface. Crimped metal strips 6 areset across the mouth of the cavity, being fixed with nails 7 to the shoulderfioor 2. The extensible curtain 8, the materials of which will be described later, is now set over the cavity mouth and fixed with tacks9 to the shoulder floor 2, over whicha layer of waterproof cement 10 has previously been spread. Metal flashingpla-tes 11 are now laid against the edge portion of the curtain 8 and are partially driven into the shoulder wall 3 below the cambium layer 5, the purpose of these flashing plates being'to prevent the callus 12 from pushing under "the edge of the curtain. 8. At the top and bottom of the cavity triangular metal plates 13 are used. The closure is completed by rubbing plastic cement 14 against the flashing nails and'the shoulder wall 3; j i l The first few years of callus growth will press against the shoulder wall 3 and the flashing plates 1]., both of which are rigid. Later the callus will roll or push against the extensible curtain 8, which will expand and recede before the callus, permitting it to grow into the cavity in the natural way and thus form the circular callus rolls which are the trees natural braces, restoring the strength lost through the presence of the wound,

best Way to form the sbeelder is $9 11? it in the wood, but a metal shoulder floor or stop 15 as shown in Fig. 5 can be used instead of the wood shoulder. The metal stop 15 is a strip of metal having bending-loops 16 and spurs l7 and is strongly fixed to the wood 1 by staples 18 placed over the loops 16. The curtain 8 is held in place by nails toenailed into the wood 1 at the loops 16. Flashing plates 11 are used over the edge of the curtain 8, as in the case of the wood shoulder.

lVhen an existing callus 20 around an old cavity can be preserved, as in Fig. 6 and Fig. 7, the closure can be set back of it. Crimped metal strips 6 are set across the cavity and are fixed with nails 7 to the inner surface of the callus 20 or to the adjacent wood. The last two or three of the strips 6can be nailed only at one side, the other side being supported by the back-filling 21, which will be-described later. The curtain 8 is now set over the strips 6 and is pushed as firmly as possible into .the angle between the strips 6 and the callus 20. Some plastic cement 14 is now pressed into the angle between the callus 20 and the curtain 8.

For the extensible curtain 8 the best material is a fabric composed in part of metal, as copper, and in part of fiber, as cotton. The metal wire provides stiffness and durability and the fiber fills the openings in the wire mesh and retains the waterproofing material, as liquidgrafting wax, which should be applied to the fabric. The material can be made with a loop weave or chain stitch or any type of Weaving or knitting in which the elements are laid together loosely with a surplus of material available to take up the extension and prevent fracture when the fabric is stretched. Or the curtain may be rendered extensible by convolutions of the fabric produced by pleating or crimping it. The curtain illustrated in the drawing is a convoluted fabric. The convolutions may take the form of simple folds, as shown at 8 in Fig. 3, or

the material may be infolded and backfolded, forming-box pleats, as shown at 8 in Fig. 4. The convolutions should be discontinuous, not running from top to bottom of the curtain but being interrupted at intervals. As

shown in curtain 8, Fig. 1, theconvolutions may be quite irregular in disposition. \Vhet-her they are arranged regularly or irregularly the pleats, in order to preserve a relatively even distribution of the surplus material, should be substantially alternate in relation so that the middle part of each lies beside the ends of the adjacent pleats. Normally only a single thickness of curtain is used, but for some purposes, as scientific experiment, a double curtain may be preferable, the outer curtain being of metal fabric and the inner curtain of a perfectly waterproof and air-tight material, as sheet rubber.

' Or the inner curtain may be of overlapped strips arranged to shed water but to permit the passage of air between them, if it is desired to ventilate the cavity, in which case the outer curtain must be permeable to air. The curtain, though it must be extensible, should not be of loose or flimsy construction. The pressure exerted by a growing callus is very great and it will spread a curtain of quite stiff material. In general the curtain should be capable of extending without rupture to two or three times its initial area.

A back filling, wholly or partly filling the cavity back of the closure, is not usually necessary in small cavities. Large cavities, to give greater support to the curtain, can be loosely packed with excelsior or other easily compressible material, treated with creosote to prevent decay. When a closure is inserted behind old calluses, as in Fig. 6 and Fig. 7 a firm back filling is an advantage, to hold the closure in place against the calluses. Attention is called to the applicants copending application Serial No. 220,402 filed $ept. 19, 1927.

I claim:

1. A tree cavity closure comprising a pleated fabric having discontinuous box pleats approximately alternate in lateral relation, the middle of each pleat being ap proximately in alignment with the ends of the laterally adjacent pleats.

2. A tree cavity closure set interiorly of the cambium layer, comprising a fabric curtain having infolded pleats.

3. A tree cavity closure comprising a curtain having box pleats of various lengths and irregular in lateral relation, the area of the material backfolded therein substantially equalling the superficial area of the curtain.

4. A tree cavity closure comprising a cur tain having surface convolutions adapting it to expand and recede rearwards into the cavity in compliance with the growth of the callus.

5. As a tree cavity closure, a curtain com prising rubber elements adapting it to expand. and recede rearwards into the cavity in compliance with the growth of the callus.

6. The method of producing a bark substitute for trees which consists in procuring a sheet of pliable material and rendering it laterally and longitudinally extensible by forming surface convolutions therein, and thereafter fitting a portion of said sheet to a shoulder cut in the Wood of the tree and thereafter fixing a plurality of plates over the external edge portion of the sheet contiguous to the wood.

7. The method of producing a bark substitute for trees which consists in weaving a fabric of fibrous and metallic elements, and

thereafter forming surface convolutions in said fabric, and thereafter cutting a curtain from the convoluted fabric, sa1d curtain being fitted to a shoulder cut in the wood of the tree, and thereafter fixing a plurality of metal plates over an external edge zone of said curtain, said plates being fixed rigidly to the tree.

8. As a tree cavity closure, a curtain comprising a fabric of loop weave adapted to expand and recede rearwards into the cavity in compliance with the growth of the callus.

In testimony whereof I afiix my signature.

ELBERT PEETS. 

